Control method of rolling of central hole defect of continuously-cast thick blank

Abstract

The invention discloses a control method of rolling of a central hole defect of a continuously-cast thick blank. The method comprises steps as follows: (1) setting of a velocity field: a round hole defect-containing kinematically admissible velocity field and a strain rate field are set; (2) a rolling power total power function is established on the basis of the velocity field, and a minimum rolling power function is obtained; (3) design of rolling process parameters; (4) calculation of a dynamic critical geometrical shape factor; (5) calculation of an actual geometrical shape factor; (6) judgment and adjustment of the rolling state. The method depends on the rolling criterion of dynamic rolling parameters, and setting of the rolling process parameters per pass can be guided, so that the percent of pass of product flaw detection is increased.

Description

technical field [0001] The present application relates to the technical field of thick plate hot rolling, in particular to a method for controlling the rolling of continuous casting thick slabs with central hole defects. Background technique [0002] There are inevitably metallurgical defects such as porosity, shrinkage cavity, and microcracks in the central area of ​​the continuous casting slab. These defects destroy the continuity of the material, reduce the fatigue resistance and fracture resistance of the material, and are the main reasons for the failure of the flaw detection of the rolled product and the restriction of the yield. Among many defects, the most influential hole defects will seriously reduce the service life of the rolled material or cause the rolled material to be scrapped. Rolling of slab center defects is of great significance to optimize rolling process parameters and improve plate quality and yield. [0003] How to effectively eliminate these centra...

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Problems solved by technology

[0005] For the compression of the central defect, the existing analytical criteria and numerical simulation critical conditions ignore the characteristics of the thickness change due to different passes of the rolled piece, and the reduction amount of each pass is designed according to the same critical value, that is, according to geometry factor and The design belongs to the static control of the reduction pass, which can only give a rough guide, and cannot reflect the influence of the changing rolling parameters of each pass on the rolling effect of the central hole defect

In particular, the simulated critical mechanical conditions can only give discrete points, which can only be applied to given specific parameters, and it is difficult to give general guidance for actual production

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